Let's say a feature like the SD card is not available. When octoprint sends the command M21, but there is no card, what is the error message?
All commands that can't be processed by the firmware are replied with an error message.
That link doesn't say what it should say if it's a command that the printer does not recognize. E.g.
N134 G114302 X10.0*10458
What would Marlin Say to the G114302 command?
My LulzBot TAZ 6 with Marlin 1.9.34 firmware says:
Send: G114302 X10.0 Recv: echo:Unknown command: "G114302 X10.0"
And your OctoPrint accepts that? "echo: Unknown command:"
I guess don't understand what you are looking for. Maybe some details on why you asked the original question might help us understand how to answer it.
I sent your command example via the OctoPrint Terminal tab and received the response as shown. To me that means OctoPrint accepted it. OctoPrint didn't crash or hang or do anything else nasty.
Well, I send back "notok" which causes OctoPrint to just stop there and wait for about a minute before continuing. Sometimes it doesn't continue and reports communication failure.
The link that @Ewald_Ikemann posted does not show "notok" as a valid reply. That could be why OctoPrint doesn't like it.
Right, but the LulzBot says "echo:Unknown command:" (and then the command). So what does "echo" do?
Some manufactures do their own thing on Marlin.
In this case, LulzBot puts an
'echo' in front of this error message.